App.net, the ad-free, Twitter-like service, has begun accepting payments via PayPal as it opens its membership process to those that prefer the online payments service, or don’t have the requisite credit card that was previously needed. It has also simplified monthly trials by removing credit card requirements.

The service has been quietly accepting PayPal payments via a dedicated link for a while but it just started doing so publicly. Founder Dalton Caldwell tells me that the aim is to “make it easier for folks to get in via various mechanisms”. That makes a lot of sense now that the service is settling down and adding new features, like private messaging, so it’s high time to broaden the payment options.

To make the payment via PayPal, users simply hit the dedicated PayPal button (highlighted below) during the sign-up process — membership costs $5 for a month, $36 for an annual subscription and $100 for a developer account.

The company made a significant change to the 30-day trials that it introduced last month. The feature allows users with annual membership to invite friends to test the service, and now the requirement of credit card details has been removed from the sign-up process.

The removal of that barrier — which was initially required in order to prepare payment for if/when trialists opted to make their membership permanent — is a no-brainer likely to boost the number of invitees on the service.

Caldwell explains that, though obvious, the change has been made now that the company was comfortable with the system.

“We rolled out the first rev of invites a couple of weeks ago and have been transparent that this is very much an experiment we are trying to learn,” he explains. “The big feedback from rev 1 was that folks didn’t want to invite people to something that requires credit card details and, after monitoring how invites were being used, we felt comfortable opening this up a bit more.”

The change is active on all 30-day invites sent out from today onward. Caldwell tells me that his team is “trying to make small, iterative changes across the board” and, since App.net remains in beta, we shouldn’t expect that to change.

The service was attracting 1,000 new members a day after the release of new mobile apps, and it continues to gain momentum, particularly among developers and tech communities. App.net is largely seen as being an ad-free Twitter alternative but, for those who have used it, that statement is somewhat unfair since it is developing into a community and social network of its own, not a copycat.